World Congress of Malacology Antwerp ... - Unitas Malacologica

patterns of several genera across different climate zones mostly invalidate the previous attempts at
zoogeographic division of Turkey using a single group (e.g. Zonitidae).
Histopathology and bioaccumulation of heavy metals (Cu & Pb) in the giant land snail
Archachatina marginata (Swainson)
Otitoloju, Adebayo A.; Ajikobi, D. A.; Egonmwan, Rosemary I.
1. Department of Zoology, University of Lagos, Akoka, Lagos, Nigeria,
Email: bayotitoloju@yahoo.com; dajikobi@yahoo.com; egone@infoweb.com.ng
Histopathological effects of heavy metals (Cu and Pb) and their bioaccumulation were assessed in the
edible giant land snail Archachatina marginata (Swainson). On the basis of 168h LC50, CuSO4.5H2O
was found to be significantly more toxic than Pb(NO3)2. The exposure of the snails to sublethal
concentrations of Cu and Pb, resulted in a prevalence of hepatocellular foci of cellular alterations
(FCA) in the digestive glands. Hepatocytes of snails exposed to sublethal concentrations of Cu were
observed to be clogged together with peripheral thickening while exposure to Pb caused
inflammation of the digestive tubules. Basophilic adenoma and ovotesticular fibrillar inclusions were
also observed in the ovotestes of exposed snails. Exposure of A. marginata ovum to sublethal
concentrations of Cu resulted in a five-fold and three-fold accumulation of the metal in the digestive
gland and foot of exposed snails compared to the control. The exposure to Pb, however, showed that
the snail had high capacity to accumulate the metal ions in both the digestive gland and foot:
compared to the control, the concentration of Pb in the digestive gland was found to be up to 375
folds and over 1000 folds was observed in the foot. The tissue alterations observed in this study
reinforce the use of histopathology in combination with monitoring of metal levels in body tissues of
edible animal as powerful tools for early monitoring anthropogenic contamination of terrestrial
environments and prevent potential public health tragedies.
First record of a species belonging to the genus Dendropoma (Mollusca, Caenogastropoda,
Vermetidae) from the rocky subtidal zone of Peninsula Mejillones, northern Chile
Pacheco, Aldo 1 ; Laudien, Jürgen 2 ; Riascos, Jose 1
1. Universidad de Antofagasta, Facultad de Recursos del Mar, Av. Angamos 601, PO Box. 117,
Antofagasta, Chile,
Email: babuchapv@yahoo.com; josemar.rv@gmail.com
2. Alfred Wegener Institute for Polar and Marine Research.,Am Alten Hafen 26, D-27568
Bremerhaven, Germany,
Email: Juergen.Laudien@awi.de
Marine gastropods belonging to the family Vermetidae are sessile. Their distribution is restricted to
tropical and subtropical latitudes (i.e. Mexico, California and West Africa) as well as to locations in
the Mediterranean Sea. Habitats comprise rocky intertidal and subtidal zones with warm and
oxygenated waters. Several clusters of Dendropoma sp. (Vermetidae) were recorded for the first time
inhabiting the rocky subtidal zone of Peninsula Mejillones, northern Chile in July 2006. Samples
were collected by SCUBA divers from the rocky “Anemones Wall” (23º28’17.30’’S,
70º37’13.80’’W) at 17m depth. This discovery extends the geographical range of the genus
Dendropoma into the Southeastern Pacific. Thus the present species is the first vermetid gastropod
able to thrive under cold upwelling conditions. As the taxonomy of vermetids is complicated due to
lacking precise morphological patterns no species assignment was attempted and a genetic study is
necessary for feasible species identification. Due to the lack of local fossil records, we hypothesize
that the species invaded the Peninsula Mejillones area and discuss three hypotheses: dispersal via (i)
larval stages, (ii) due to anthropogenic activities (ship fouling, ballast water), or (iii) rafting. We
concluded that the invasion by rafting is the most possible explanation. Funding for field trips was
provided by “Programa Bicentenario de Ciencia y Tecnologia” PBCT and the INCO – EU project
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